John Carroll was influential in expanding the Catholic Church in the United States. He became an ordained Jesuit priest in 1765. After serving on a diplomatic committee during the Revolutionary War, Carroll became a prominent leader in the campaign to build the Catholic Church in the United States. In response to prompting on the part of Carroll and several other priests to officially organize the American church, the Vatican chose Carroll to lead the country’s Catholic mission in 1784. In 1789, it named him the Bishop of the Diocese of Baltimore, itself the first Catholic diocese in the United States. In 1808, he became Archbishop of Baltimore. At the time of his death in 1815, the Catholic Church in the United States had grown to five dioceses.

John Carroll was born in 1735 to one of the most prominent Catholic families of Maryland. He was the cousin of Charles Carroll of Carrollton, a signer of the Declaration of Independence. Carroll was ordained a Jesuit priest in French Flanders in 1765, taught throughout Europe for several years, and returned to Maryland eight years later after Pope Clement XIV suppressed his religious order.In 1776, Carroll was appointed by the Continental Congress to be part of a diplomatic committee, along with Benjamin Franklin, Samuel Chase, and his cousin Charles, which was tasked with attracting Canada to the American fight for independence. After the war, Carroll became a prominent leader in the campaign to build the Catholic Church in the United States. In response to prompting on the part of Carroll and several other priests to officially organize the American church, the Vatican chose Carroll to lead the country’s Catholic mission in 1784. In 1789, it named him the Bishop of the Diocese of Baltimore, itself the first Catholic diocese in the United States, following an election by his fellow priests; he became Archbishop of Baltimore in 1808. As bishop, Carroll oversaw the founding of Georgetown Academy (the present-day Georgetown University) as well as St. Mary’s Seminary and St. Joseph’s College in Maryland.Functioning as a predecessor of sorts to Bishop John England of the Diocese of Charleston, Carroll became an early proponent of church synods and a degree of republicanism in local churches, though still maintaining the power of the hierarchy and reinforcing the ultimate primacy of the papacy. He oversaw the expansion of the institutional Catholic Church into the Northeast, New England, the South, and the Appalachian West. He also oversaw the creation of several new dioceses, which were fueled in large part by the arrival of European missionary priests, including Stephen Badin, the first Catholic priest ordained by Carroll in the United States. At the time of his death in 1815, the church in the United States had grown to five dioceses.